From New England to the Pacific Northwest, airport terminals in the 1990s are being designed and built to meet foreseeable demand--with very little uncommitted space. The speculative nature of terminal building design and planning, dominant a decade ago, has been replaced by a philosophy more attuned to today's realities of consolidation of carriers, shared use of facilities, a slowed passenger growth rate and high debt loads for carriers and airport operators. New or expanded terminals at Manchester Airport in New Hampshire and T.F. Green State Airport in Providence, R.I.; Portland (Ore.) International Airport; Syracuse-Hancock International Airport in New York, and Greater Rochester international Airport in New York, and Greater Rochester International Airport in New York, are examples of projects undertaken in direct response to air traffic demands.